Distraction effects of in-car tasks with a touch screen based navigation system user interface were studied in a driving simulator experiment with eye tracking. The focus was to examine which particular in-car task components visually distract drivers the most. The results indicate that all of the visual-manual in-car tasks led to increased levels of experienced demands and to lower driving speeds. The most significant finding was that text entry and kinetic scrolling of lists were the main sources of visual distraction whereas simple selection tasks with familiar target locations led to least severe distraction effects.